Production of fine-metal tungsten.



E. THOMSON- f PRODUCTION OF FINE METAL TUNGSTEN.

APPLICATION FILED PEB.19, 1908.

960,441 Patented June 7 1910.

Witnesses Ihventbr Elihu Thomson, I 5% Hgdroge Reservoir To all whom it may concern:

nmT D STATES PATENT OFFICE.

ELIHU momson, or S'WAMPSCOTT, imassacnusnrrs, AssIeNon '10 GENERAL 'nnnc'rmc comramr, A conronnrron or NEW YORK.

raonuc'rroisr or munem'ran 'rurres'rnn;

I 3e it known that I, ELIHU THOMSON, a citizen of the United States, residing at Swampscott, county of Essex, State of Massachusetts, have invented certain new and useful Improvements'in the Production of Fine-Meta Tungsten, of which the following is a specification. Y

My invention relates to the reductionv of, metals by a gaseous reducing medium.

It is desirable for some purposes to obtain metals in a finely divided state, with the exclusion of all impurities.- A very pure,

finely divided metal can-be best obtained by carefully purifying some reduciblecompound ofthe-metal, as the oxid, and then efecting .a reduction of the finely divided o'kid with a pure reducing gas, as hydrogen. As finely divided ,metals are easily oxidized when heated, great care must be used to guard against the heated reduced metal coming in contact with air, or the 'watery vapor which results as a by-product in the 1 reaction.

According to my invention I employ a furnace which will accomplish a contmuous reduction of metallic compounds, as tungsten oxid, at any desired rate, using for this purpose a reducing gas such as hydrogen. As only a small part of thehydrogen is used up'in the reaction when hydrogen as is passed over a metallic oxid, I provi e for the removal; of the watery vapor, and return the hydrogen to the furnace to be again used inthe reducing process.

f The features-of novelty-of my invention are pointed out with particularity in the claims, but a better understanding of my 'inventionmay be obtained from the following description taken in connection with the accompanying drawing.

The reducible tungsten com ound, as tungstic oxid, W0,, is conveye into the vid'ed with a rotatable Archimedean screw 3,v which serves to move the oxid along the reducing chamber atany desired rate. The reduced .metal falls into the receiving hopper 4:. The Archimedean screw is rotated at any desired rate,'- and is connected by means of the gear 5 to any suitable source of power, such .as' the motor The hydrogen enters at the oppositeend of the reducing re-oxidation is, therefore, v linear speed of this moving stream of hyvdrogen chamber 1 from where a greater part of the chamber and passes through the same. The streams ofoxid and hydrogen, therefore, move in opposite directions. The reducible oxid is conveyed into the reducing chamber 1 from the ho er 2 by means of the rotatable member 7, which is provided with a slotted portion 8. The rotatable member 7 is connected to anysuitable source of power, as the motor 9, and in its revolution the slotted portion 8, in passing through the hopper containing the oxid, picks up a portion of oxid and transfers it to the reducing chamber. By this arrangement the oxid is fed uniformly into the furnace and air is kept out of the reduction chamber. The reduced'metal is conveyed out of the hopper 4 into a receiving vessel 10, in a similar manner by means of the rotatin member 11, which is likewise provided wit a slotted ortion 12.

The re ucing chamber is heated through a portion of its length by any suitable means,

such as the gas burners 13. lhe temperature of this hot zone should be somewhere Patented June'fl, 1910.

between 600 to 800 C. -As the dry hydrogen gas meets the tungstic .oicid in' the hot zone,

reduction takes place according to the following reaction WO +6H=W+3H,O.

As before stated, the stream of hydrogen and the tungstic oxid move in opposite d1 rections, therefore the watery vapor resultreaction is carried y the hying from the from the reduced metal, and

drogen away must be great enough to carry away avoided. The

the moisture at a rate which will exceed the rate of diifusionlof the watery vapor in the opposite direction. The hydrogen, laden with watery vapor, is drawn from the reducing chamber by means of a pump 1 1 through a tube 15. The pump may be connected to any suitable source of power. As Shown on the drawing, it is connected to the motor 9. The hydrogen is conveyed by the pump through a water-cooled condenser 15,

watery vapor is condensed. The condensed moisture trickles down into a receiving vessel 16. The unused hydi'ogen still containing a certain amount of uncondensed moisture is carried by means of the tube 17 to a vessel 18, where it comes in contact with metallic alkali, such as sodium. The following reaction takes place:

As will be seen, the hydrogen is regenerated with the formation of sodium hydroxid. The unused hydrogen,-together with this regenerated hydrogen, is carried back to the reducing chamber through a tube 19, and is used again for the purpose of reduction. The vessel 18, instead of containing a metallic alkali for the purpose of regenerating hydrogen from the moisture, may contain a moisture-absorbing agent, such as sulfuric acid or calcium chlorid, and the moisture may thus be absorbed; the, unused hydrogen, as before, being returned to the reducing chamber, In either case any losses What I claim as new and desire to secure by Letters Patent of the United States, is,

1. The process which consists in reducing metallic oxid with hydrogen, recovering at v least'a part of the'hydrogen from the watery vapor formed in the reaction, adding the recovered hydrogen to the main body of 40 hydrogen, and using the combined body of I gas to reduce another'portion of oxid.

2. The process of continuously reducing metallic compounds, which consists in continuously feedin the compound to and through a zone 0 treatment, simultaneously passing hydrogen gas through said zone, removing the watery vapor from the unused hydrogen, and returning the hydrogen to the zone of treatment in a continuous cycle.

3. The process of' continuously reducing metallic oxid, which consists in continuously feeding the oxid to and through the zone of treatment, simultaneously passing hydrogen gas through the zone, regenerating hydrogen 5 y from the watery vapor formed by the reaction, and adding theregenerated hydrogen to the main current of hydrogen in a continuous cycle.

In witness whereof, I have hereunto set my hand this fifteenth day of February,

ELIHU THOMSON. Witnesses:

JOHN A. MCMANUS, Jr., CHARLES A. Barnum). 

